Me: but this thing will not fix. See that thing that will fix!! (begins to work on fix)

Them: I don't understand why doing this thing is a problem!!!

Me: it's not a problem. I will do it, I promise*. But it's not a fix for that problem. I have made a fix for that problem. I thought you'd prefer me to explain why doing the thing would not help in this situation.

Why not simply do this thing and say: "See? It doesn't help, just like I predicted."? You will loose time of course - but maybe not so much of nerves? (And as a person practically living on the other side of the conflict, I'd say to you that it may save not only your nerves, but the other person's too.)

Usually, I do, but this would be several hours work when they are already asking for a bunch of other stuff as well, and on this particular job I have repeatedly had a scenario where I've done as asked, then they have complained about the cost of paying me when nothing much has been achieved (even when I said that would happen). It's a difficult balance: if I just do as told, then I get people saying the value for money is poor: if I try to educate them, then they think I'm being argumentative.

It would be so nice to be able to just advise someone that a slightly different approach would work better and have them actually listen.

" I've done as asked, then they have complained about the cost of paying me when nothing much has been achieved (even when I said that would happen)"Well, in that case I would be complitely on your side - but that woudn't help you much, would it? (Where is the sign of a sad smile?) It's very irritating when people complain about the price AFTER the job is done AND everything goes as they were told.